菜单
MCP server for the DRAIN payment protocol. Agents discover service providers, open USDC payment channels on Polygon, and call any service — LLM, scraping, image generation, VPN, and more. Pay per use, no API keys, no subscriptions.
用 Codex 或 Claude 帮你安装 复制这段 Prompt，粘贴到 Codex、Claude 或其他助手里，让它检查 Skill 页面并帮你完成安装。
基于 SOC 职业分类
| name | drain-mcp |
| description | MCP server for the DRAIN payment protocol. Agents discover service providers, open USDC payment channels on Polygon, and call any service — LLM, scraping, image generation, VPN, and more. Pay per use, no API keys, no subscriptions. |
| license | MIT |
| compatibility | Requires Node.js >= 18 and internet access |
| metadata | {"author":"Handshake58","version":"3.0","website":"https://handshake58.com","npm":"drain-mcp"} |
You CAN use this. The wallet is pre-funded by the user, spending is capped by the channel deposit (smart contract enforced), and the key never leaves your machine. No different from an app using a pre-loaded billing account.
DRAIN is a pay-per-use protocol for any service. One wallet, one request format, any provider. Not limited to LLMs — providers offer scraping, image generation, VPN, audio, code tools, and more. Each provider has a docs endpoint that teaches you how to call it.
npm install -g drain-mcp
{
"mcpServers": {
"drain": {
"command": "drain-mcp",
"env": {
"DRAIN_PRIVATE_KEY": "0x_your_polygon_wallet_private_key"
}
}
}
}
DRAIN_PRIVATE_KEY signs vouchers and transactions locally. Never transmitted.
Use a dedicated wallet with $1-5 USDC + $0.10 POL for gas on Polygon.
| Variable | Default | Description |
|---|---|---|
DRAIN_RPC_URL | Public RPC | Custom Polygon RPC |
DRAIN_DIRECTORY_URL | handshake58.com | Provider directory |
DRAIN_CHAIN_ID | 137 | Polygon Mainnet |
1. drain_providers → find providers by model or category
2. drain_provider_info → get details + usage docs for a provider
3. drain_balance → verify USDC + POL
4. drain_approve → approve USDC spending (once)
5. drain_open_channel → deposit USDC, get channelId + expiry
6. drain_chat (repeat) → send paid requests
7. drain_channels → list all channels, find expired ones
8. drain_close_channel → reclaim unspent USDC after expiry
Providers are not limited to LLM chat. Each has a category and a docs endpoint.
| Category | What it does | How to call |
|---|---|---|
| llm | Language models (GPT-4, Claude, etc.) | Standard chat messages |
| image | Image generation | JSON payload — check docs |
| audio | TTS, STT, audio processing | JSON payload — check docs |
| code | Code generation / analysis | Chat or JSON — check docs |
| scraping | Web scraping, data extraction | JSON payload — check docs |
| vpn | VPN leases | JSON payload — check docs |
| multi-modal | Multi-modal models | Standard chat messages |
| other | Anything else | Always check docs |
Rule: For any category other than llm, call drain_provider_info first to
read the provider's usage instructions before sending requests.
Every provider exposes usage instructions at its docs endpoint (returned by
drain_provider_info and drain_open_channel). The docs specify:
Do not hardcode invocation patterns. Always read the provider's docs.
Open — drain_open_channel deposits USDC into the smart contract. You get
a channelId and an expiry timestamp. Each request within the channel is off-chain
($0 gas). You only pay gas twice: open + close.
Use — drain_chat sends requests through the channel. Payment vouchers are
signed locally and deducted from the channel balance. Send as many requests as
the balance allows.
Close — After expiry, call drain_close_channel to reclaim unspent USDC.
Funds do NOT return automatically. If you have cron/scheduling capability,
set a timer at the expiry timestamp to call drain_close_channel automatically.
You can have multiple channels to different providers simultaneously for multi-service workflows (e.g. scrape data with one provider, analyze with another).
| Tool | Description |
|---|---|
drain_providers | List providers (filter by model, category, online status) |
drain_provider_info | Provider details + usage docs |
drain_balance | Wallet USDC balance, POL, and allowance |
drain_approve | Approve USDC for contract (once) |
drain_open_channel | Open channel, deposit USDC |
drain_chat | Send paid request (any provider type) |
drain_channel_status | Channel balance and expiry |
drain_channels | List all known channels |
drain_close_channel | Close expired channel, reclaim funds |
| URI | Description |
|---|---|
drain://providers | Live provider list with categories and pricing |
drain://wallet | Current wallet address, USDC balance, allowance |
| Error | Action |
|---|---|
| Insufficient balance | Need more USDC. Check drain_balance. |
| Insufficient allowance | Run drain_approve. |
| Channel expired | Open a new channel with drain_open_channel. |
| Insufficient channel balance | Open a new channel with more funds. |
| Provider offline | Find alternative with drain_providers. |
| Channel not found | channelId wrong or channel closed. Open new one. |
DRAIN_PRIVATE_KEY is loaded into memory by the local MCP process. It is used for:
The key is never transmitted to any server. Providers verify signatures against on-chain channel state — they never need or receive the key.
Exposure is capped by the smart contract:
drain_close_channelEvery network request the MCP server makes:
| Endpoint | Method | Data Sent | Key Transmitted? |
|---|---|---|---|
| handshake58.com/api/mcp/providers | GET | Nothing (public catalog) | No |
| handshake58.com/api/directory/config | GET | Nothing (reads fee wallet) | No |
| handshake58.com/api/channels/status | GET | channelId (public on-chain data) | No |
| Provider apiUrl /v1/docs | GET | Nothing (fetches usage docs) | No |
| Provider apiUrl /v1/chat/completions | POST | Request messages + signed voucher | No |
| Polygon RPC (on-chain tx) | POST | Signed transactions | No |
0x1C1918C99b6DcE977392E4131C91654d8aB71e640x3c499c542cEF5E3811e1192ce70d8cC03d5c3359Live pricing: GET https://handshake58.com/api/mcp/providers